Multiple access in wireless telecommunications system for high-mobility applications

ABSTRACT

A wireless telecommunications system that mitigates infrasymbol interference due to Doppler-shift and multipath and enables multiple access in one radio channel. Embodiments of the present invention are particularly advantageous for wireless telecommunications systems that operate in high-mobility environments, including high-speed trains and airplanes.

STATEMENT OF RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/153,577, filed on 5 Oct. 2018, which is a continuation of U.S. patentapplication Ser. No. 15/410,622, filed on 19 Jan. 2017, now U.S. Pat.No. 10,098,092, issued 9 Oct. 2018, which claims benefit of U.S.provisional patent application No. 62/316,243, filed on 31 Mar. 2016,entitled “Robust Wireless Telecommunications System”, and U.S.provisional patent application No. 62/316,298, filed on 31 Mar. 2016,entitled “Orthogonal Time Frequency Space” all of which are incorporatedby reference.

The following patent applications are incorporated by reference:

-   -   U.S. patent application Ser. No. 15/146,987, filed on 5 May        2016, entitled “Wireless Telecommunications System for        High-Mobility Applications”, and    -   U.S. patent application Ser. No. 15/215,007, filed on 20 Jul.        2016, entitled “Multiple Access in Wireless Telecommunications        System for High-Mobility Applications”, and    -   U.S. patent application Ser. No. 15/410,578, filed on 19 Jan.        2017, entitled “Wireless Telecommunications System for        High-Mobility Applications”.

FIELD OF THE INVENTION

The present invention relates to wireless telecommunications in general,and, more particularly, to a wireless telecommunications system that candetect and mitigate impairments to its radio signals.

BACKGROUND OF THE INVENTION

A radio signal can be impaired as it propagates from a transmitter to areceiver, and the value of a wireless telecommunications system issubstantially dependent on how well the system mitigates the effects ofthose impairments. In some cases, the transmitter can take preventativemeasures, and in some cases the receiver can take remedial measures.

SUMMARY OF THE INVENTION

The present invention is a wireless telecommunications system thatavoids some of the costs and disadvantages associated with wirelesstelecommunications systems in the prior art. For example, theillustrative embodiments of the present invention use a modulatedradio-frequency carrier signal to convey data items wirelessly through aradio-frequency environment that comprises natural and man-maderadio-frequency carrier signal-path impairments (e.g., objects, etc.)that reflect, refract, diffract, and absorb the modulatedradio-frequency carrier signal.

A consequence of the presence of the signal-path impairments is that theradio receiver receives both direct-path and multipath images of thesignal, which can cause infra-symbol and inter-symbol interference. Theillustrative embodiments of the present invention are able todiscriminate between direct-path and multipath images, which(substantially) prevents infra-symbol interference and enables theremediation of inter-symbol interference. Furthermore, the illustrativeembodiments are also particularly effective remediating the effects ofDoppler-shift impairments in the radio channel.

The illustrative embodiment of the present invention modulates theradio-frequency carrier signal with waveforms that are constructed to(substantially) prevent infra-symbol interference and enable theremediation of inter-symbol interference and Doppler-shift impairments.

As described in detail below, the nature of the waveforms is such thattemporally-longer waveforms are better at preventing infra-symbolinterference but introduce greater latency to the communications.Therefore, temporally-longer waveforms are less suitable for data itemsthat are less latency tolerant (e.g., bi-directional voicecommunications, etc.) but more acceptable for data items that are highlatency tolerant (e.g., broadcast uni-directional television, etc.).Temporally-longer waveforms are also advantageous as pilot signals andto discover the precise nature of the signal-path impairments.

In contrast, temporally-shorter waveforms are less effective inpreventing infra-symbol interference but are more suitable for lowlatency tolerant data items. The illustrative embodiments of the presentinvention enables temporally-longer waveforms and temporally-shorterwaveforms to be used concurrently in the same communications channel.This is advantageous for several reasons, including but not limited to,the ability of the telecommunications system to adapt on-the-fly the mixof longer and shorter waveforms based on the latency tolerance of thedata items queued for transmission.

Furthermore, embodiments of the present invention enable a plurality oftransmitters to simultaneously transmit (radiate) into the same radiochannel to a single receiver in such a way that the receiver canseparate the individual transmissions and properly associate them withtheir respective transmitters. This is widely called “multiple access”and is well known in other telecommunications systems (e.g.,frequency-division multiple access, time-division multiple access,code-division multiple-access, etc.).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a block diagram of the salient components of wirelesstelecommunications system 100 in accordance with the illustrativeembodiment of the present invention.

FIG. 1B depicts a block diagram of the salient components of basestation 120 in accordance with the illustrative embodiment of thepresent invention.

FIG. 1C depicts a block diagram of the salient components of wirelessterminal 130-a, wherein a∈{1, 2}, in accordance with the illustrativeembodiment of the present invention.

FIG. 2a depicts a flowchart of the salient tasks performed by basestation 120, wireless terminal 130-1, and wireless terminal 130-2 inaccordance with the illustrative embodiment of the present invention.

FIG. 2b depicts a flowchart of the salient tasks performed by basestation 120, wireless terminal 130-1, and wireless terminal 130-2 in theperformance of task 201.

FIG. 3 depicts a waveform array Φ1 is based on M1 orthogonal M1-arystepped-pulse waveforms.

FIG. 4a depicts a plot of where the energy associated with waveformφ1(1,1) of waveform array Φ1 (M1=6, N1=4) beginning at superframe timeinterval 1 is deposited into a 10 MHz radio channel.

FIG. 4b depicts a plot of where the energy associated with waveformφ1(1,1) of waveform array Φ1 (M1=6, N1=4) beginning at superframe timeinterval 25 is deposited into a 10 MHz radio channel.

FIG. 4c depicts a plot of where the energy associated with waveformφ2(1,1) of waveform array Φ2 (M2=6, N2=8) beginning at superframe timeinterval 1 is deposited into a 10 MHz radio channel.

FIG. 5a depicts a plot of where the energy associated with all of thewaveforms from waveform arrays Φ1 assigned to base station 130-1 isdeposited beginning at superframe time interval 1.

FIG. 5b depicts a plot of where the energy associated with all of thewaveforms from waveform arrays Φ1 assigned to base station 130-1 isdeposited beginning at superframe time interval 25.

FIG. 5c depicts a plot of where the energy associated with all of thewaveforms from waveform arrays Φ2 assigned to base station 130-1 isdeposited beginning at superframe time interval 1.

FIG. 5d depicts a plot of where the energy associated with all of thewaveforms from waveform arrays Φ1 assigned to base station 130-2 isdeposited beginning at superframe time interval 1.

FIG. 5e depicts a plot of where the energy associated with all of thewaveforms from waveform arrays Φ1 assigned to base station 130-2 isdeposited beginning at superframe time interval 25.

FIG. 5f depicts a plot of where the energy associated with all of thewaveforms from waveform arrays Φ2 assigned to base station 130-2 isdeposited beginning at superframe time interval 1.

FIG. 6 depicts a flowchart of the salient tasks associated with task202-a, wherein a∈{1, 2}, in accordance with the illustrative embodimentof the present invention.

DETAILED DESCRIPTION

FIG. 1A depicts a block diagram of the salient components of wirelesstelecommunications system 100 in accordance with the illustrativeembodiment of the present invention. Wireless telecommunications system100 comprises: base station 120, wireless terminal 130-1, and wirelessterminal 130-2, all of which are situated in geographic region 110.

In accordance with the illustrative embodiment, base station 120provides bi-directional wireless telecommunications service to wirelessterminal 130-1 and wireless terminal 130-2.

In accordance with the illustrative embodiment, base station 120provides telecommunications service by exchanging “data items” withwireless terminal 130-1 and wireless terminal 130-2, which data itemsrepresent sound, images, video, data, and signaling. It will be clear tothose skilled in the art how to make and use base station 120, wirelessterminal 130, and wireless terminal 130-2 so that they can de-constructsound, images, video, data, and signaling into data items, and it willbe clear to those skilled in the art how to make and use base station120, wireless terminal 130, and wireless terminal 130-2 so that they canre-construct sound, images, video, data, and signaling from those dataitems.

In accordance with the illustrative embodiment, each data item isrepresented by a complex number that corresponds to one symbol in a 16quadrature-amplitude (“16 QAM”) signal constellation modulation scheme.It will be clear to those skilled in the art, however, after readingthis disclosure, how to make and use alternative embodiments of thepresent invention in which each data item corresponds to a symbol in anydigital modulation scheme (e.g., frequency-shift keying, amplitude-shiftkeying, phase-shift keying, etc.).

In accordance with the illustrative embodiment, wirelesstelecommunications system 100 comprises one base station and twowireless terminals, but it will be clear to those skilled in the art,after reading this disclosure, how to make and use alternativeembodiments of the present invention that comprise any number of basestations and any number of wireless terminals. Furthermore, it will beclear to those skilled in the art how to partition the radio spectrum inan area into radio channels and to assign those channels to the basestations.

In accordance with the illustrative embodiment, base station 120 isstationary and terrestrial, but it will be clear to those skilled in theart, after reading this disclosure, how to make and use alternativeembodiments of the present invention in which each base station 120 ismobile or airborne, or mobile and airborne.

In accordance with the illustrative embodiment, wireless terminal 130-1and wireless terminal 130-2 are mobile, but it will be clear to thoseskilled in the art, after reading this disclosure, how to make and usealternative embodiments of the present invention in which each wirelessterminal is either mobile or stationary.

In accordance with the illustrative embodiment, geographic region 110comprises natural and man-made radio-frequency objects (not shown) thatreflect, refract, and diffract the carrier signals that propagatebetween base station 120 and wireless terminal 130-1 and wirelessterminal 130-2. Furthermore, some of the radio-frequency objects arestationary (e.g., trees, hills, buildings, etc.) and some are mobile(e.g., trucks, ships, airplanes, etc.).

In accordance with the illustrative embodiment, the parameters thatcharacterize the signal-path impairments in the radio channel betweenbase station 120 and wireless terminal 130-1 and wireless terminal 130-2are dynamic (i.e., change with respect to time). It will be clear tothose skilled in the art, after reading this disclosure, how to make anduse embodiments of the present invention in which the characteristics ofthe radio channel and the nature of the signal-path impairments arestatic (i.e., do not change with respect to time).

In accordance with the illustrative embodiment, base station 120 andwireless terminal 130-1 and wireless terminal 130-2 exchange modulatedradio-frequency carrier signals in a radio channel that is B=10 MHzwide. It will be clear to those skilled in the art, however, afterreading this disclosure, how to make and use alternative embodiments ofthe present invention in which the radio channel has a differentbandwidth (e.g., 2.5 MHz, 5.0 MHz, 12.5 MHz, 15 MHz, 20 MHz, 40 MHz, 80MHz, etc.).

FIG. 1B depicts a block diagram of the salient components of basestation 120 in accordance with the illustrative embodiment of thepresent invention. Base station 120 comprises: encoder 121, modulator122, power amplifier 123, and antenna 124, low-noise amplifier 125,demodulator 126, decoder 127, and processor 128.

Encoder 121 comprises the hardware and software necessary to compress,encrypt, and add forward error correction to the data items to betransmitted to wireless terminal 130-1 and wireless terminal 130-2. Itwill be clear to those skilled in the art how to make and use encoder121.

Modulator 122 comprises the hardware and software necessary to modulatea radio-frequency carrier signal with the data items from encoder 121 togenerate a modulated radio-frequency carrier signal. The constructionand operation of modulator 122 is described in detail herein and in theaccompanying figures.

Power amplifier 123 comprises the hardware necessary to increase thepower of the modulated radio-frequency carrier signal for transmissionvia antenna 124. It will be clear to those skilled in the art how tomake and use power amplifier 123.

Antenna 124 comprises the hardware necessary to facilitate the radiationof the modulated radio-frequency carrier signal wirelessly through spaceto wireless terminal 130-1 and wireless terminal 130-2. It will be clearto those skilled in the art how to make and use antenna 124.

Low-Noise amplifier 125 comprises the hardware necessary to increase thepower of the modulated radio-frequency carrier signal received viaantenna 124. It will be clear to those skilled in the art how to makeand use low-noise amplifier 125.

Demodulator 126 comprises the hardware and software necessary to:

-   -   i. demodulate the modulated radio-frequency carrier signal        received by antenna 124, which is the sum of a first modulated        radio-frequency carrier signal transmitted by wireless terminal        130-1 and a second modulated radio-frequency carrier signal        transmitted by wireless terminal 130-2, and    -   ii. recover one or more data items transmitted by wireless        terminal 130-1 that are embodied in the modulated        radio-frequency carrier signal and to associate those data items        with wireless terminal 130-1, and    -   iii. recover one or more data items transmitted by wireless        terminal 130-2 that are embodied in the modulated        radio-frequency carrier signal and to associate those data items        with wireless terminal 130-2.        It will be clear to those skilled in the art, after reading this        disclosure, how to make and use demodulator 126.

Decoder 127 comprises the hardware and software necessary to decompress,decrypt, and correct the data items transmitted by wireless terminal130-1 and wireless terminal 130-2. It will be clear to those skilled inthe art how to make and use decoder 127.

Processor 128 comprises the hardware and software necessary to operatebase station 120 and to interface with the cellular infrastructure (notshown in FIG. 1B). It will be clear to those skilled in the art, afterreading this disclosure, how to make and use processor 128.

FIG. 1C depicts a block diagram of the salient components of wirelessterminal 130-a, wherein a∈{1, 2}, in accordance with the illustrativeembodiment of the present invention. Wireless terminal 130-a comprises:encoder 131-a, modulator 132-a, power amplifier 133-a, and antenna134-a, low-noise amplifier 135-a, demodulator 136-a, decoder 137-a,processor 138-a, and user interface 139-a.

Encoder 131-a comprises the hardware and software necessary to compress,encrypt, and add forward error correction to the data items to betransmitted to base station 120. It will be clear to those skilled inthe art how to make and use encoder 131-a.

Modulator 132-a comprises the hardware and software necessary tomodulate a radio-frequency carrier signal with the data items fromencoder 131-a to generate a modulated radio-frequency carrier signal.The construction and operation of modulator 132-a is described in detailherein and in the accompanying figures.

Power amplifier 133-a comprises the hardware necessary to increase thepower of the modulated radio-frequency carrier signal for transmissionvia antenna 134-a. It will be clear to those skilled in the art how tomake and use power amplifier 133-a.

Antenna 134-a comprises the hardware necessary to facilitate theradiation of the modulated radio-frequency carrier signal wirelesslythrough space to base station 120. It will be clear to those skilled inthe art how to make and use antenna 134-a.

Low-Noise amplifier 135-a comprises the hardware necessary to increasethe power of the modulated radio-frequency carrier signals received viaantenna 134-a. It will be clear to those skilled in the art how to makeand use low-noise amplifier 135-a.

Demodulator 136-a comprises the hardware and software necessary todemodulate a modulated radio-frequency carrier signal transmitted bybase station 120 to recover the data items transmitted by base station120. It will be clear to those skilled in the art, after reading thisdisclosure, how to make and use demodulator 136-a.

Decoder 137-a comprises the hardware and software necessary todecompress, decrypt, and correct the data items transmitted by basestation 120. It will be clear to those skilled in the art how to makeand use decoder 137-a.

Processor 138-a comprises the hardware and software necessary to operatewireless terminal 130-a and to interface with user interface 139-a. Itwill be clear to those skilled in the art, after reading thisdisclosure, how to make and use processor 138-a.

User interface 139-a comprises the hardware and software necessary toenable a user (not shown) to interact with wireless terminal 130-a. Itwill be clear to those skilled in the art how to make and use userinterface 139-a.

FIG. 2a depicts a flowchart of the salient tasks performed by basestation 120, wireless terminal 130-1, and wireless terminal 130-2 inaccordance with the illustrative embodiment of the present invention.

At task 201, base station 120, wireless terminal 130-1, and wirelessterminal 130-2 establish the parameters of two non-identical waveformarrays—waveform arrays Φ1 and Φ2—with which they will communicate. Inaccordance with the illustrative embodiment, base station 120, wirelessterminal 130-1, and wireless terminal 130-2 establish the parameters oftwo non-identical waveforms arrays but it will be clear to those skilledin the art, after reading this disclosure, how to make and usealternative embodiments of the present invention that establish theparameters of any number (e.g., three, four, six, eight, twelve,sixteen, thirty-two, sixty-four, etc.) of non-identical waveform arrays.Task 201 is described in detail below and in the accompanying figures.

At task 202, wireless terminal 130-1 and wireless terminal 130-2 eachtransmit (radiate) a modulated radio-frequency carrier signal in a radiochannel to base station 120 in accordance with the parameters ofwaveform arrays Φ1 and Φ2. Task 202 is described in detail below and inthe accompanying figures.

At task 203, base station 120 receives a radio-frequency signal from theradio channel that is a sum of:

-   -   1. the modulated radio-frequency carrier signal radiated by        wireless terminal 130-1, plus    -   2. the multipath images (if any) of the modulated        radio-frequency carrier signal radiated by wireless terminal        130-1, plus    -   3. the modulated radio-frequency carrier signal radiated by        wireless terminal 130-2, plus    -   4. the multipath images (if any) of the modulated        radio-frequency carrier signal radiated by wireless terminal        130-2, plus    -   5. noise.        As part of task 203, base station 120 demodulates and decodes        the radio-frequency signal to recover one or more data items        transmitted by wireless terminal 130-1 (and to associate those        data items with wireless terminal 130-1) and one or more data        items transmitted by wireless terminal 130-2 (and to associate        those data items with wireless terminal 130-2). It will be clear        to those skilled in the art, after reading this disclosure, how        to make and use base station 120 to be able to perform task 230.

At task 204, base station 120 transmits one or more data itemsassociated with wireless terminal 130-1 and one or more data itemsassociated with wireless terminal 130-2 to the cellular infrastructure(e.g., a mobile switching center, etc.), which is not shown in FIG. 1B.

FIG. 2b depicts a flowchart of the salient tasks performed by basestation 120, wireless terminal 130-1, and wireless terminal 130-2 in theperformance of task 201. As part of task 120, the parameters of waveformarrays Φ1 and Φ2 are chosen to:

-   -   i. mitigate infra-symbol interference caused by Doppler-shift        and multipath interference in the radio channel, and    -   ii. enable simultaneous multiple access by both wireless        terminal 130-1 and wireless terminal 130-2 to base station 120,        and    -   iii. enable wireless terminal 130-1 to transmit waveforms of        waveform arrays Φ1 and Φ2 into the radio channel at the same        time (i.e., concurrently) while wireless terminal 130-2        transmits different waveforms of waveform arrays Φ1 and Φ2 into        the same radio channel.

At task 210, and as is described in detail below, each waveform array Φjis characterized by two parameters Mj and Nj, wherein Mj and Nj are apositive integers greater than one and j∈{1, 2} (i.e., waveform array Φ1is characterized by parameters M1 and N1 and waveform array Φ2 ischaracterized by parameters M2 and N2).

In accordance with the first illustrative embodiment, M1=M2=6, N1=4, andN2=8 (i.e., M1=M2 and N1≠N2). In accordance with the second illustrativeembodiment, M1=16, M2=32, and N1=N2=8 (i.e., M1≠M2 and N1=N2). Inaccordance with the third illustrative embodiment, M1=16, M2=32, N1=32,and N2=8 (i.e., M1≠M2 and N1≠N2). In all three illustrative embodiments,M1·N1≠M2·N2.

It will be clear to those skilled in the art, after reading thisdisclosure, how to make and use alternative embodiments of the presentinvention with any combination of values of M1, M2, N1, and N2.Furthermore, it will be clear to those skilled in the art, after readingthis disclosure, that embodiments of the present invention are typicallysimplified and more efficient by making M2 an integral multiple of M1(e.g., 2×, 3×, 4×, 5×, 6×, 8×, 12×, 16×, 32×, 64×, 128×, etc.). Andstill furthermore, it will be clear to those skilled in the art, afterreading this disclosure, that embodiments of the present invention aretypically simplified and more efficient by making N2 an integralmultiple of N1 (e.g., 2×, 3×, 4×, 5×, 6×, 8×, 12×, 16×, 32×, 64×, 128×,etc.).

In accordance with the illustrative embodiment, the parameters ofwaveform arrays Φ1 and Φ2 are established once when base station 120,wireless terminal 130-1, and wireless terminal 130-2 first establishcommunication, but it will be clear to those skilled in the art, afterreading this disclosure, how to make and use alternative embodiments ofthe present invention in which base station 120, wireless terminal130-1, and wireless terminal 130-2 periodically or sporadicallyre-establish the parameters of waveform array Φ1 or waveform array Φ2 orwaveform arrays Φ1 and Φ2. For example and without limitation, basestation 120, wireless terminal 130-1, and wireless terminal 130-2 canre-establish the parameters of waveform arrays Φ1 and Φ2 when:

-   -   i. the traits of the signal path from change, or    -   ii. the type of data represented by the data items changes, or    -   iii. the latency tolerance of the data items changes, or    -   iv. any combination of i, ii, and iii.

As is described in detail below, waveform arrays Φ1 and Φ2 comprisewaveforms that convey data items from wireless terminal 130-1 orwireless terminal 130-2 to base station 120. In accordance with theillustrative embodiment, wireless terminal 130-1 and wireless terminal130-2 convey low-latency tolerant data items using waveform array Φ1 andhigh-latency tolerant data items using waveform array Φ2. It will beclear to those skilled in the art, after reading this disclosure, how tomake and use alternative embodiments of the present invention in whichwireless terminal 130-1 and wireless terminal 130-2 use the waveforms indifferent waveform arrays for:

-   -   i. different conditions of the signal path from wireless        terminal 130-1 or wireless terminal 130-2 to base station 120,        or    -   ii. different types of data items, or    -   iii. different latency tolerance of the data items, or    -   iv. any combination of i, ii, and iii.

Basic Waveforms—

Waveform array Φj is based on an extension of Mj basic waveforms bj(1),. . . , bj(mj), . . . , bj(Mj) that are orthogonal in Mj-dimensionalvector space, where Mj is a positive integer greater than 1, and mj is apositive integer in the range mj∈{1, . . . , Mj}.

In accordance with all of the illustrative embodiments, basic waveformbj(mj) is waveform mj of a Mj-ary stepped-pulse waveform scheme, asdepicted in FIG. 3. In accordance with all of the illustrativeembodiments, each pulse is a band-limited raised-cosine pulse but itwill be clear to those skilled in the art, after reading thisdisclosure, how to make and use alternative embodiments of the presentinvention in which each pulse has a different shape.

Each pulse in basic waveform bj(mj) is band-limited, and, therefore, theduration of each pulse is 1/B seconds, wherein B is the bandwidth of thechannel. Furthermore, the centers of adjacent pulses are separated by1/B seconds. And still furthermore, the total duration of each basicwaveform bj(mj) is Mj/B seconds.

Although all of the illustrative embodiments uses stepped-pulsewaveforms as the basic waveforms, it will be clear to those skilled inthe art, however, after reading this disclosure, how to make and usealternative embodiments of the present invention in which waveform arrayΦj is based on any set of Mj orthogonal waveforms, bj(1), . . . ,bj(Mj).

Structure of Waveform Array Φ—

Waveform array Φj comprises Mj·Nj waveforms that are orthogonal inMj·Nj-dimensional vector space. The Mj·Nj waveforms of waveform array Φjare denoted φ(1,1), . . . , φj(mj,nj), . . . , φj(Mj,Nj), where nj is apositive integer in the range nj∈{1, . . . , Nj}.

Each waveform φj(mj,nj) is the sum of Nj waveforms yj(mj,nj,1), . . . ,yj(mj,nj,pj), . . . , yj(mj,nj,Nj).

Each waveform φj(mj,nj) is identically partitioned into Nj time slots 1,. . . , pj, . . . , Nj, where pj is a positive integer in the rangepj∈{1, . . . , Nj}. Waveform yj(mj,nj,pj) occupies time slot pj inwaveform φj(mj,pj) and equals:yj(mj,nj,pj)=bj(mj)·u(nj,pj)  (Eq. 1)wherein u(nj,pj) is a phasor that equals:u(nj,pj)=exp(2π(nj−1)(pj−1)i/Nj)  (Eq. 2)The duration of waveform φ(mj,nj,pj) defines the duration of time slotpj.

The Mj·Nj waveforms of waveform array Φj partition the time-frequencyspace of the modulated radio-frequency carrier signal into 1/Bsecond-long “time intervals” and Mj·Nj “frequency sub-bands.” Eachwaveform array Φj constitutes a “frame” of Mj·Nj time intervals, and theleast common multiple of Mj·Nj for all j (e.g., the LCM(M1·N1, M2·N2)for j∈{1, 2}) constitutes a “superframe” of time intervals. The temporalstart of each waveform is specified relative to the first time intervalin the superframe.

A salient characteristic of the illustrative embodiment is that eachwaveform φj(mj,nj) in waveform array Φj deposits energy into:

-   -   i. unique time-frequency portions the radio channel, and    -   ii. 1/Mj·Nj^(th) of the radio channel during the frame of        waveform array Φj.        This is illustrated in FIGS. 4a, 4b, and 4c for waveform array        Φ1 (M1=6, N1=4) and waveform array Φ2 (M2=6, N2=8).

For example, FIG. 4a depicts a plot of where the energy associated withwaveform φ1(1,1) of waveform array Φ1 (M1=6, N1=4) beginning atsuperframe time interval 1 is deposited into a 10 MHz radio channel. InFIG. 4a the radio channel is depicted as divided into twenty-four(M1·N1=24) 416.66 KHz frequency sub-bands (B=10 MHz/M1·N1=24) andforty-eight [LCM(M1·N1, M2·N2)=24] 0.1 microsecond (1/B=10 MHz) timeintervals. In FIG. 4a , it can be seen that energy is deposited only intime intervals 1, 7, 13, and 19 and only in the frequency sub-bands0-0.416 MHz, 1.666-2.083 MHz, 3.333-3.750 MHz, 5.000-5.417 MHz,6.666-7.083 MHz, and 8.333-8.750 MHz in the channel.

FIG. 4b depicts a plot of where the energy associated with waveformφ1(1,1) of waveform array Φ1 (M1=6, N1=4) beginning at superframe timeinterval 25 is deposited into a 10 MHz radio channel. In FIG. 4a theradio channel is depicted as divided into twenty-four (M1·N1=24) 416.66KHz frequency sub-bands (B=10 MHz/M1·N1=24) and forty-eight [LCM(M1·N1,M2·N2)=24] 0.1 microsecond (1/B=10 MHz) time intervals. In FIG. 4b , itcan be seen that energy is deposited only in time intervals 25, 31, 37,and 43 and only in the frequency sub-bands 0-0.416 MHz, 1.666-2.083 MHz,3.333-3.750 MHz, 5.000-5.417 MHz, 6.666-7.083 MHz, and 8.333-8.750 MHzin the channel.

Similarly, FIG. 4c depicts a plot of where the energy associated withwaveform φ2(1,1) of waveform array Φ2 (M2=6, N2=8) beginning atsuperframe time interval 1 is deposited into a 10 MHz radio channel. InFIG. 4a the radio channel is depicted as divided into twenty-four(M1·N1=24) 416.66 KHz frequency sub-bands (B=10 MHz/M1·N1=24) andforty-eight [LCM(M1·N1, M2·N2)=24] 0.1 microsecond (1/B=10 MHz) timeintervals. In FIG. 4c , it can be seen that energy is deposited only intime intervals 1, 7, 13, 19, 25, 31, 37, and 43 and only in thefrequency sub-bands 0-0.208 MHz, 1.666-1.875 MHz, 3.333-3.541 MHz,5.000-5.208 MHz, 6.666-6.875 MHz, and 8.333-8.541 MHz in the channel.

It will be clear to those skilled in the art how to determine when andwhere any given waveform φj(mj,nj) will deposit energy into a radiochannel using Fourier analysis in well-known fashion.

In accordance with the illustrative embodiment, base station 120 selectsindividual waveforms from waveform arrays Φ1 and Φ2 to convey data itemsfrom wireless terminal 130-1 and wireless terminal 130-2, and selectsthose waveforms so that:

-   -   I. no two waveforms overlap the time-frequency space of the        modulated radio-frequency carrier signal (to prevent        inter-symbol interference), and    -   II. all of the time-frequency space of the modulated        radio-frequency carrier signal has energy deposited into it (to        maximize spectral efficiency), and    -   III. waveforms from waveform array Φ1 convey data items with        low-latency tolerance and waveforms from waveform array Φ2        convey data items with high-latency tolerance.        To accomplish this, base station 120 instructs wireless terminal        130-1 and wireless terminal 130-2 how to transmit waveforms from        waveform array Φ1 and waveforms from waveform array Φ2 into the        same channel at the same time with satisfactory guard waveforms        (i.e., how to transmit waveforms from waveform array Φ1 and        waveforms from waveform array Φ2 so that they:    -   1. overlap in the 4.8 microsecond superframe “time space” of the        radio channel, and    -   2. overlap in the 10 MHz “frequency space” of the radio channel,        and    -   3. do not overlap in the “time-frequency space” of the radio        channel.

For example, FIGS. 5a, 5b, 5c, 5d, 5e, and 5f depict waveforms in whichwaveforms from waveform arrays Φ1(M1=6, N1=4) and Φ2(M2=6, N2=8) areeither exclusively:

-   -   1. assigned to base station 130-1 to transmit data items to base        station 120, or    -   2. assigned to base station 130-2 to transmit data items to base        station 120, or    -   3. reserved as guard waveforms (and not transmitted by either        base station 130-1 or base station 130-2.

Base station 130-1 is assigned four waveforms from waveform array Φ1beginning at superframe time interval 1 and superframe time interval 25,as shown in Table 1 and as depicted in FIGS. 5a and 5b , respectively.

TABLE 1 Waveforms from Waveform Array Φ1 Assigned to Base Station 130-1Conveying Beginning Waveform Superframe Time Interval φ1(1,1) 1, 25φ1(1,2) 1, 25 φ1(4,3) 1, 25 φ1(5,3) 1, 25

Base station 130-1 is also assigned twelve waveforms from waveform arrayΦ2 beginning at superframe time interval 1, as shown in Table 2 and asdepicted in FIG. 5c .

TABLE 2 Waveforms from Waveform Array Φ2 Assigned to Base Station 130-1Conveying Beginning Waveform Superframe Time Interval φ2(1,1) 1 φ2(1,2)1 φ2(1,3) 1 φ2(2,1) 1 φ2(2,3) 1 φ2(2,4) 1 φ2(4,5) 1 φ2(4,6) 1 φ2(4,7) 1φ2(5,5) 1 φ2(5,6) 1 φ2(5,7) 1

It will be clear to those skilled in the art, after reading thisdisclosure, that base station 130-1 can transmit (in a singlesuperframe) only those combinations of waveforms assigned to it that donot interfere with each other (i.e., do not put energy into the same“time-frequency space” of the radio channel). Furthermore, it will beclear to those skilled in the art, after reading this disclosure, whichcombinations of waveforms can be transmitted (in a single superframe) soas to not interfere with each other.

Base station 130-2 is assigned four waveforms from waveform array Φ1beginning at superframe time interval 1 and superframe time interval 25,as shown in Table 3 and as depicted in FIGS. 5d and 5e , respectively.

TABLE 3 Waveforms from Waveform Array Φ1 Assigned to Base Station 130-2Conveying Beginning Waveform Superframe Time Interval φ1(1,3) 1, 25φ1(2,3) 1, 25 φ1(4,1) 1, 25 φ1(5,1) 1, 25

Base station 130-2 is also assigned twelve waveforms from waveform arrayΦ2 beginning at superframe time interval 1, as shown in Table 4 and asdepicted in FIG. 5f .

TABLE 4 Waveforms from Waveform Array Φ2 Assigned to Base Station 130-2Conveying Beginning Waveform Superframe Time Interval φ2(1,5) 1 φ2(1,6)1 φ2(1,7) 1 φ2(2,5) 1 φ2(2,6) 1 φ2(2,7) 1 φ2(4,1) 1 φ2(4,2) 1 φ2(4,3) 1φ2(5,1) 1 φ2(5,2) 1 φ2(5,3) 1

It will be clear to those skilled in the art, after reading thisdisclosure, that base station 130-1 can transmit (in a singlesuperframe) only those combinations of waveforms assigned to it that donot interfere with each other (i.e., do not put energy into the same“time-frequency space” of the radio channel). Furthermore, it will beclear to those skilled in the art, after reading this disclosure, whichcombinations of waveforms can be transmitted (in a single superframe) soas to not interfere with each other.

The remaining waveforms—which were not assigned to either base station130-1 or base station 130-2—are reserved as guard waveforms in order toreduce inter-symbol interference from multi-path images and Dopplershifts.

It will be clear to those skilled in the art, after reading thisdisclosure, how to make and use alternative embodiments of the presentinvention that assign any combination of waveforms for conveying dataitems and any combination of waveforms for use as guard waveforms.Furthermore, it will be clear to those skilled in the art, after readingthis disclosure, how to partition the waveforms in waveform array Φamong any number of wireless terminals and guard waveforms.

At task 211, base station 120 transmits the waveform array Φ parametersto wireless terminal 130-1 and wireless terminal 130-2 along with acommand to transmit into the radio channel using the assigned waveforms.

At task 212, wireless terminal 130-1 receives the waveform array Φparameters and the command to use the waveforms assigned to it.

At task 213, wireless terminal 130-2 receives the waveform array Φparameters and the command to use the waveforms assigned to it.

FIG. 6 depicts a flowchart of the salient tasks associated with task202-a, wherein a∈{1, 2}, in accordance with the illustrative embodimentof the present invention.

At task 1601, wireless terminal 130-a establishes a one-to-onerelationship between each data item it will transmit to base station 120and each waveform Φ(m,n) in waveform array Φ that has been assigned toit. As part of task 1601, wireless terminal 130-a modulates aradio-frequency carrier signal with each waveform assigned to it and thecorresponding data item to generate a modulated radio-frequency carriersignal. It will be clear to those skilled in the art, after reading thisdisclosure, how to make and use embodiments of the present inventionthat perform task 1601.

At task 1602, the modulated radio-frequency carrier signal is radiatedinto the radio channel via antenna 134-a for reception by base station120. It will be clear to those skilled in the art, after reading thisdisclosure, how to make and use embodiments of the present inventionthat perform task 1602.

Markman Definitions

Orthogonal—For the purpose of this specification, two waveforms areorthogonal if their inner product is zero over the time interval ofinterest.

Identical Waveform Arrays—For the purposes of this specification,waveform array Φ1(M1, N1) and waveform array Φ2(M2, N2) are identical ifM1=M2 and N1=N2.

Non-identical Waveform Arrays—For the purposes of this specification,waveform array Φ1(M1, N1) and waveform array Φ2(M2, N2) arenon-identical if they are not identical.

What is claimed is:
 1. A base station apparatus, comprising: a processorconfigured to: transmit: (a) a first command to a first wirelessterminal to transmit, into a radio channel during a frame, a firstmodulated radio-frequency carrier signal that is modulated with a firstwaveform φ(1,1) and a first data item d(1,1), and (b) a second commandto a second wireless terminal to transmit, into the radio channel duringthe frame, a second modulated radio-frequency carrier signal that ismodulated with a second waveform φ(M,1) and a second data item d(M,1),wherein: (i) the waveform φ(m,n) is partitioned into N time slots 1, . .. , p, . . . , N, (ii) time slot p of the waveform φ(m,n) comprises abasic waveform b(m) multiplied by exp[2π(n−1)(p−1)i/N], (iii) the firstwaveform φ(1,1) is multiplied by the first data item d(1,1), and thesecond waveform φ(M,1) is multiplied by the second data item d(M,1),(iv) M and N are positive integers greater than 1, (v) m is a positiveinteger in the range m∈{1, . . . , M}, and (vi) n and p are positiveintegers in the range n∈{1, . . . , N}; receive, from the radio channelduring the frame, a third modulated radio-frequency carrier signal viaan antenna; demodulate the third modulated radio-frequency carriersignal to recover the first data item d(1,1) and the second data itemd(M,1); and transmit the first data item d(1,1) in association with thefirst wireless terminal and the second data item d(M,1) in associationwith the second wireless terminal.
 2. The base station apparatus ofclaim 1, wherein j and k are positive integers in the range m∈{1, . . ., M}, and wherein a basic waveform b(j) and a basic waveform b(k) areorthogonal for j≠k.
 3. The base station apparatus of claim 1, whereinthe basic waveform b(m) is waveform m in an M-ary stepped-pulse waveformscheme.
 4. The base station apparatus of claim 1, wherein the bandwidthof the radio channel is B Hz, and the duration of the basic waveformb(m) is M/B seconds.
 5. The base station apparatus of claim 1, whereinthe bandwidth of the radio channel is B Hz, and the duration of thewaveform φ(m,n) is MN/B seconds.
 6. A base station apparatus,comprising: a processor configured to: transmit: (a) a first command toa first wireless terminal to transmit, into a radio channel during aframe, a first modulated radio-frequency carrier signal that ismodulated with a first waveform φ(1,1) and a first data item d(1,1), and(b) a second command to a second wireless terminal to transmit, into theradio channel during the frame, a second modulated radio-frequencycarrier signal that is modulated with a second waveform φ(1,N) and asecond data item d(1,N), wherein: (i) the waveform φ(m,n) is partitionedinto N time slots 1, . . . , p, . . . , N, (ii) time slot p of thewaveform φ(m,n) comprises a basic waveform b(m) multiplied byexp[2π(n−1)(p−1)i/N], (iii) the first waveform φ(1,1) is multiplied bythe first data item d(1,1), and the second waveform φ(1,N) is multipliedby the second data item d(1,N), (iv) M and N are positive integersgreater than 1, (v) m is a positive integer in the range m∈{1, . . . ,M}, and (vi) n and p are positive integers in the range n∈{1, . . . ,N}; receive, from the radio channel during the frame, a third modulatedradio-frequency carrier signal via an antenna; demodulate the thirdmodulated radio-frequency carrier signal to recover the first data itemd(1,1) and the second data item d(1,N); and transmit the first data itemd(1,1) in association with the first wireless terminal and the seconddata item d(1,N) in association with the second wireless terminal. 7.The base station apparatus of claim 6, wherein j and k are positiveintegers in the range m∈{1, . . . , M}, and wherein a basic waveformb(j) and a basic waveform b(k) are orthogonal for j≠k.
 8. The basestation apparatus of claim 6, wherein the basic waveform b(m) iswaveform m in an M-ary stepped-pulse waveform scheme.
 9. The basestation apparatus of claim 6, wherein the bandwidth of the radio channelis B Hz, and the duration of the basic waveform b(m) is M/B seconds. 10.The base station apparatus of claim 6, wherein the bandwidth of theradio channel is B Hz, and the duration of the waveform φ(m,n) is MN/Bseconds.
 11. A base station apparatus, comprising: a processorconfigured to: transmit: (a) a first command to a first wirelessterminal to transmit, into a radio channel during a frame, a firstmodulated radio-frequency carrier signal that is modulated with a firstwaveform φ(1,1) and a first data item d(1,1), and (b) a second commandto a second wireless terminal to transmit, into the radio channel duringthe frame, a second modulated radio-frequency carrier signal that ismodulated with a second waveform φ(M,N) and a second data item d(M,N),wherein: (i) the waveform φ(m,n) is partitioned into N time slots 1, . .. , p, . . . , N, (ii) time slot p of the waveform φ(m,n) comprises abasic waveform b(m) multiplied by exp[2π(n−1)(p−1)i/N], (iii) the firstwaveform φ(1,1) is multiplied by the first data item d(1,1), and thesecond waveform φ(M,N) is multiplied by the second data item d(M,N),(iv) M and N are positive integers greater than 1, (v) m is a positiveinteger in the range m∈{1, . . . , M}, and (vi) n and p are positiveintegers in the range n∈{1, . . . , N}; receive, from the radio channelduring the frame, a third modulated radio-frequency carrier signal viaan antenna; demodulate the third modulated radio-frequency carriersignal to recover the first data item d(1,1) and the second data itemd(M,N); and transmit the first data item d(1,1) in association with thefirst wireless terminal and the second data item d(M,N) in associationwith the second wireless terminal.
 12. The base station apparatus ofclaim 11, wherein j and k are positive integers in the range m∈{1, . . ., M}, and wherein a basic waveform b(j) and a basic waveform b(k) areorthogonal for j≠k.
 13. The base station apparatus of claim 11, whereinthe basic waveform b(m) is waveform m in an M-ary stepped-pulse waveformscheme.
 14. The base station apparatus of claim 11, wherein thebandwidth of the radio channel is B Hz, and the duration of the basicwaveform b(m) is M/B seconds.
 15. The base station apparatus of claim11, wherein the bandwidth of the radio channel is B Hz, and the durationof the waveform φ(m,n) is MN/B seconds.
 16. A base station apparatus,comprising: a processor configured to: transmit: (a) a first command toa first wireless terminal to transmit, into a radio channel during aframe, a first modulated radio-frequency carrier signal that ismodulated with a first waveform φ(M,1) and a first data item d(M,1), and(b) a second command to a second wireless terminal to transmit, into theradio channel during the frame, a second modulated radio-frequencycarrier signal that is modulated with a second waveform φ(1,N) and asecond data item d(1,N), wherein: (i) the waveform φ(m,n) is partitionedinto N time slots 1, . . . , p, . . . , N, (ii) time slot p of thewaveform φ(m,n) comprises a basic waveform b(m) multiplied byexp[2π(n−1)(p−1)i/N], (iii) the first waveform φ(M,1) is multiplied bythe first data item d(M,1), and the second waveform φ(1,N) is multipliedby the second data item d(1,N), (iv) M and N are positive integersgreater than 1, (v) m is a positive integer in the range m∈{1, . . . ,M}, and (vi) n and p are positive integers in the range n∈{1, . . . ,N}; receive, from the radio channel during the frame, a third modulatedradio-frequency carrier signal via an antenna; demodulate the thirdmodulated radio-frequency carrier signal to recover the first data itemd(M,1) and the second data item d(1,N); and transmit the first data itemd(M,1) in association with the first wireless terminal and the seconddata item d(1,N) in association with the second wireless terminal. 17.The base station apparatus of claim 16, wherein j and k are positiveintegers in the range m∈{1, . . . , M}, and wherein a basic waveformb(j) and a basic waveform b(k) are orthogonal for j≠k.
 18. The basestation apparatus of claim 16, wherein the basic waveform b(m) iswaveform m in an M-ary stepped-pulse waveform scheme.
 19. The basestation apparatus of claim 16, wherein the bandwidth of the radiochannel is B Hz, and the duration of the basic waveform b(m) is M/Bseconds.
 20. The base station apparatus of claim 16, wherein thebandwidth of the radio channel is B Hz, and the duration of the waveformφ(m,n) is MN/B seconds.
 21. A wireless communication system, comprising:a first wireless terminal, comprising: a first processor configured to:receive a first command to transmit a first modulated radio-frequencycarrier signal into a radio channel during a frame, wherein the firstmodulated radio-frequency carrier signal is modulated with a firstwaveform φ(1,1) and a first data item d(1,1), and wherein: (i) thewaveform φ(m,n) is partitioned into N time slots 1, . . . , p, . . . ,N, (ii) time slot p of the waveform φ(m,n) comprises a basic waveformb(m) multiplied by exp[2π(n−1)(p−1)i/N], (iii) the first waveform φ(1,1)is multiplied by the first data item d(1,1), (iv) M and N are positiveintegers greater than 1, (v) m is a positive integer in the range m∈{1,. . . , M}, and (vi) n and p are positive integers in the range n∈{1, .. . , N}, and modulate a first radio-frequency carrier signal with thefirst waveform φ(1,1) and the first data item d(1,1) to generate thefirst modulated radio-frequency carrier signal; and a first antennaconfigured to: radiate the first modulated radio-frequency carriersignal into the radio channel during the frame; and a second wirelessterminal, comprising: a second processor configured to: receive at asecond wireless terminal a second command to transmit a second modulatedradio-frequency carrier signal into the radio channel during the frame,wherein the second modulated radio-frequency carrier signal is modulatedwith a second waveform φ(M,N) and a second data item d(M,N), andmodulate at the second wireless terminal a second radio-frequencycarrier signal with the second waveform φ(M,N) and the second data itemd(M,N) to generate the second modulated radio-frequency carrier signal;and a second antenna configured to: radiate the second modulatedradio-frequency carrier signal into the radio channel during the frame.22. The wireless communication system of claim 21, wherein j and k arepositive integers in the range m∈{1, . . . , M}, and wherein a basicwaveform b(j) and a basic waveform b(k) are orthogonal for j≠k.
 23. Thewireless communication system of claim 21, wherein the basic waveformb(m) is waveform m in an M-ary stepped-pulse waveform scheme.
 24. Thewireless communication system of claim 21, wherein the bandwidth of theradio channel is B Hz, and the duration of the basic waveform b(m) isM/B seconds.
 25. The wireless communication system of claim 21, whereinthe bandwidth of the radio channel is B Hz, and the duration of thewaveform φ(m,n) is MN/B seconds.
 26. A wireless communication system,comprising: a first wireless terminal, comprising: a first processorconfigured to: receive a first command to transmit a first modulatedradio-frequency carrier signal into a radio channel during a frame,wherein the first modulated radio-frequency carrier signal is modulatedwith a first waveform φ(M,1) and a first data item d(M,1), and wherein:(i) the waveform φ(m,n) is partitioned into N time slots 1, . . . , p, .. . , N, (ii) time slot p of the waveform φ(m,n) comprises a basicwaveform b(m) multiplied by exp[2π(n−1)(p−1)i/N], (iii) the firstwaveform φ(M,1) is multiplied by the first data item d(M,1), (iv) M andN are positive integers greater than 1, (v) m is a positive integer inthe range m∈{1, . . . , M}, and (vi) n and p are positive integers inthe range n∈{1, . . . , N}, and modulate a first radio-frequency carriersignal with the first waveform φ(M,1) and the first data item d(M,1) togenerate the first modulated radio-frequency carrier signal; and a firstantenna configured to: radiate the first modulated radio-frequencycarrier signal into the radio channel during the frame; and a secondwireless terminal, comprising: a second processor configured to: receiveat a second wireless terminal a second command to transmit a secondmodulated radio-frequency carrier signal into the radio channel duringthe frame, wherein the second modulated radio-frequency carrier signalis modulated with a second waveform φ(1,N) and a second data itemd(1,N), and modulate at the second wireless terminal a secondradio-frequency carrier signal with the second waveform φ(1,N) and thesecond data item d(1,N) to generate the second modulated radio-frequencycarrier signal; and a second antenna configured to: radiate the secondmodulated radio-frequency carrier signal into the radio channel duringthe frame.
 27. The wireless communication system of claim 26, wherein jand k are positive integers in the range m∈{1, . . . , M}, and wherein abasic waveform b(j) and a basic waveform b(k) are orthogonal for j≠k.28. The wireless communication system of claim 26, wherein the basicwaveform b(m) is waveform m in an M-ary stepped-pulse waveform scheme.29. The wireless communication system of claim 26, wherein the bandwidthof the radio channel is B Hz, and the duration of the basic waveformb(m) is M/B seconds.
 30. The wireless communication system of claim 26,wherein the bandwidth of the radio channel is B Hz, and the duration ofthe waveform φ(m,n) is MN/B seconds.